Ultrafast laser induced magnetization reversal in L10 FePt films with high perpendicular magnetic anisotropy was investigated using single- and double-pulse excitations. Single-pulse excitation beyond 10 mJ cm−2 caused magnetization (M) reversal at the applied fields much smaller than the static coercivity of the films. For double-pulse excitation, both coercivity reduction and reversal percentage showed a rapid and large decrease with the increasing time interval (Δt) of the two pulses in the range of 0–2 ps. In this Δt range, the maximum demagnetization (ΔMp) was also strongly attenuated, whereas the integrated demagnetization signals over more than 10 ps, corresponding to the average lattice heat effect, showed little change. These results indicate that laser induced M reversal in FePt films critically relies on ΔMp. Because ΔMp is determined by spin temperature, which is higher than lattice temperature, utilizing an ultrafast laser instead of a continuous-wave laser in laser-assisted M reversal may reduce the overall deposited energy and increase the speed of recording. The effective control of M reversal by slightly tuning the time delay of two laser pulses may also be useful for ultrafast spin manipulation.Ultrafast laser induced magnetization reversal in L10 FePt films with high perpendicular magnetic anisotropy was investigated using single- and double-pulse excitations. Single-pulse excitation beyond 10 mJ cm−2 caused magnetization (M) reversal at the applied fields much smaller than the static coercivity of the films. For double-pulse excitation, both coercivity reduction and reversal percentage showed a rapid and large decrease with the increasing time interval (Δt) of the two pulses in the range of 0–2 ps. In this Δt range, the maximum demagnetization (ΔMp) was also strongly attenuated, whereas the integrated demagnetization signals over more than 10 ps, corresponding to the average lattice heat effect, showed little change. These results indicate that laser induced M reversal in FePt films critically relies on ΔMp. Because ΔMp is determined by spin temperature, which is higher than lattice temperature, utilizing an ultrafast laser instead of a continuous-wave laser in laser-assisted M reversal may re...

中文翻译：

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使用双激光脉冲激发揭示超快退磁过程对 L10 FePt 磁化反转的影响

使用单脉冲和双脉冲激发研究了具有高垂直磁各向异性的 L10 FePt 薄膜中的超快激光诱导磁化反转。超过 10 mJ cm-2 的单脉冲激发在远小于薄膜静态矫顽力的外加场中引起磁化 (M) 反转。对于双脉冲激励，矫顽力降低和反转百分比随着两个脉冲在 0-2 ps 范围内的时间间隔 (Δt) 的增加而迅速而大幅度地降低。在这个 Δt 范围内，最大退磁 (ΔMp) 也强烈衰减，而超过 10 ps 的积分退磁信号（对应于平均晶格热效应）几乎没有变化。这些结果表明，激光诱导 FePt 薄膜中的 M 反转严重依赖于 ΔMp。由于 ΔMp 由高于晶格温度的自旋温度决定，因此在激光辅助 M 反转中使用超快激光器代替连续波激光器可以降低总沉积能量并提高记录速度。通过微调两个激光脉冲的时间延迟来有效控制 M 反转也可用于超快自旋操纵。使用单脉冲和双脉冲激发研究了具有高垂直磁各向异性的 L10 FePt 薄膜中的超快激光诱导磁化反转。超过 10 mJ cm-2 的单脉冲激发在远小于薄膜静态矫顽力的外加场中引起磁化 (M) 反转。对于双脉冲激励，随着两个脉冲在 0-2 ps 范围内的时间间隔 (Δt) 增加，矫顽力降低和反转百分比均显示出快速而大幅度的降低。在这个 Δt 范围内，最大退磁 (ΔMp) 也强烈衰减，而超过 10 ps 的积分退磁信号（对应于平均晶格热效应）几乎没有变化。这些结果表明，激光诱导 FePt 薄膜中的 M 反转严重依赖于 ΔMp。由于 ΔMp 是由高于晶格温度的自旋温度决定的，因此在激光辅助 M 反转中使用超快激光而不是连续波激光可能会重新... 而超过 10 ps 的综合退磁信号（对应于平均晶格热效应）几乎没有变化。这些结果表明，激光诱导 FePt 薄膜中的 M 反转严重依赖于 ΔMp。由于 ΔMp 是由高于晶格温度的自旋温度决定的，因此在激光辅助 M 反转中使用超快激光而不是连续波激光可能会重新... 而超过 10 ps 的综合退磁信号（对应于平均晶格热效应）几乎没有变化。这些结果表明，激光诱导 FePt 薄膜中的 M 反转严重依赖于 ΔMp。由于 ΔMp 是由高于晶格温度的自旋温度决定的，因此在激光辅助 M 反转中使用超快激光而不是连续波激光可能会重新...